The invention relates to apparatus such as mining shovels and the like. More particularly, the invention relates to such apparatus in which a revolving frame assembly is rotatable about a center gudgeon supported by a carbody. Still more particularly, the invention relates to the bottom retainer for a center gudgeon.
A conventional mining shovel includes a carbody supported for movement over the ground by a pair of crawler assemblies. The carbody has therein a cylindrical bore centered on a vertical axis, and a cylindrical center gudgeon extends through the bore. The center gudgeon is held into place relative to the carbody primarily by an interference fit. An upper portion of the center gudgeon extends above the carbody, and a revolving frame assembly is rotatable about the upper portion of the center gudgeon. A roller circle surrounds the center gudgeon and rotatably supports the revolving frame assembly above the carbody. A lower portion of the center gudgeon extends below the carbody and includes a circumferential groove and a flat. As a "second line of defense" to prevent the center gudgeon from moving upwardly relative to the carbody, a bottom retainer engages the carbody and the lower portion of the center gudgeon.
A prior art bottom retainer is illustrated in FIGS. 1 and 2. The bottom retainer includes a split collar 1 seated in the groove 2 in the center gudgeon 3. The split collar 1 includes two or more arcuate sections 4. Each arcuate section 4 includes, at its opposite ends, radially outwardly extending ears or lugs 5, and the lugs of adjacent arcuate sections are bolted together to retain the collar sections in the groove 2. The split collar 1 engages the lower surface of the carbody 6 to prevent upward movement of the center gudgeon 3 relative to the carbody in the event the interference fit between the center gudgeon and the carbody fails to prevent such upward movement.
The bottom retainer also includes a key 7 which is located below the split collar 1 and which has a flat surface 8 engaging the flat 9 on the center gudgeon 3. The key is welded to the split collar at 10, and the split collar is welded to the carbody at 11 so that the split collar and the key cannot rotate relative to the carbody. Engagement of the flat on the center gudgeon by the key prevents rotation of the center gudgeon relative to the carbody.